electric motors

• the direction of the motor can be reversed either by swapping the polarity of the dc supply or swapping the magnetic poles over. change the direction of the current every half turn
• increase speed of rotations by:

  -increasing current

  -add more turns to coil

  -increase magnetic flux density by using more powerful magnets
• the split ring commutator

  swaps the positive and negative connections every half turn

  this means direction of current will swap every half turn

  forces on coil will always be acting in the same direction , coil rotates in same direction. this changes direction of current every half turn
• in a wire, the current goes prom positive to negative, meaning current is going in different directions . on right side front to back. on left back to front
• place the loop of wire in a magnetic field. the wire experiences a force on right and left side. force on left hand side acts upwards, force on right hand side acts downwards. loop will rotate in clockwise direction
• once the loop is at 90 degrees it will stop rotating. if it reaches beyond 90 degrees then the direction of current means that the force on the left hand side is now acting downwards, and force on right hand side is upwards